A variety of systems for sampling fluids from reactors and tanks are known. However, numerous disadvantages and shortcomings exist with prior systems, and there is a need for improvement to overcome such disadvantages and shortcomings.
Some examples of commercially-available prior fluid-sampling devices are the "Safesamp Reactor Sampling Systems" sold by Technova AG, of Sweden, and the "Neotecha Sampling Systems" sold by Grinnell Corporation, of Exeter, N.H.
The Safesamp system's basic arrangement includes a flanged dip pipe for connection to the tank with the dip pipe extending downwardly into the fluid in the tank, a bottom flange with a suction hose mounted at the top and extending downward through the dip pipe and into the tank fluid and a perpendicular connection port in communication with the dip pipe to pressurize the tank. The bottom flange is connected to a flanged "charging" ball valve. A middle flange is connected to the charging valve and has a sightglass with a ball float mounted on top and a perpendicular port located below the sightglass to direct flow for sampling. An upper flange is mounted on top of the sightglass and includes the sightglass ball seat, perpendicular connections for auxiliaries and a perpendicular port for a vent return. The perpendicular sampling port located in the middle flange is connected to a flanged isolation ball valve which is connected to the sampling assembly. The sampling assembly includes a sample bottle which is vented through another isolation ball valve which is connected to the vent return port in the upper flange.
To obtain a sample, the "charging" ball valve is opened (the sampling isolation valve is closed) and the fluid is drawn up through the suction tube (by supplying, if need, a vacuum via the upper flange connection or pressurizing the tank via the lower flange connection). The fluid flows upwardly, fills the perpendicular sampling port in the middle flange (to the isolation ball valve) and continues filling the sightglass. As fluid fills the sightglass, the ball float rises with the level until it reaches the top of the sightglass where the ball then seats against the ball seat located in the upper flange and flow stops. The operator closes the "charging" ball valve and opens the sampling isolation valve and the vent valve. The fluid flows by gravity from the sightglass through the perpendicular sampling port in the middle flange, through the sampling isolation valve and into the sample bottle. Any entrapped gases are vented through the vent connection located between the sampling bottle and the vent return line.
The above-described sampling system has drawbacks in that the sample fluid volume would consist of partial previous sampling fluid if the system is not purged after each sampling, or would nonetheless consist of the first volume of fluid that is drawn from the top of the tank without any system fluid flushing first. It would be preferable to drain off the first and perhaps subsequent volumes of fluid so that the fluid sent to the sampling bottle is a sample that has not been mixed with previous samples or other contaminants. Such sampling system can only get an unmixed sample within the sampling bottle by drawing numerous cycles of fluid through the system. This is a time-consuming and inconvenient process, and is wasteful of the often expensive chemicals being mixed in the reactor vessel.
The aforementioned Neotecha systems, sold by Grinnell Corporation, are generally similar to the above-described Safesamp Samplers. The Neotecha system samples fluid from reactors for continuous media circulation and pH monitoring. The Neotecha samplers utilize double-diaphragm pumps and are relatively compact in design. The Neotecha samplers also use lined stainless steel braided hoses and connections to facilitate quick start-ups and convenient changes. They have a pH probe connection device which allows adaptation to most commercially-available pH probes, and various auxiliary ports to facilitate cleaning of wetted surfaces and additional vessel access.
However, the Neotecha systems have the problem that, when chemical compositions in the reactor vessel have particulates or become viscous to some extent, the compositions can tend to clog or damage the pump. This leads to costly down time for cleaning and repair.
These and other existing devices for sampling fluids from reactor vessels have significant problems. This invention addresses and overcomes such problems.